<application 
    android:icon="@drawable/ic_launcher" 
    android:label="@string/app_name" 
    > 
    <activity 
      android:name="ApplicationDemoActivity" 
      android:label="@string/app_name" > 
      <intent-filter> 
        <action android:name="androidintentactionMAIN" /> 
        <category android:name="androidintentcategoryLAUNCHER" /> 
      </intent-filter> 
    </activity> 
  </application> 

package com.tutor.application; 
 
import androidappApplication; 
import androidcontentContext; 
 
public class MainApplication extends Application { 
 
  /** 
   * 全局的上下文 
   */ 
  private static Context mContext; 
   
  @Override 
  public void onCreate() { 
    superonCreate(); 
     
    mContext = getApplicationContext(); 
     
  }   
   
  /**获取Context 
   * @return 
   */ 
  public static Context getContext(){ 
    return mContext; 
  } 
   
   
  @Override 
  public void onLowMemory() { 
    superonLowMemory(); 
  } 
   
   
} 

<?xml version="1.0" encoding="utf-8"?> 
<manifest xmlns:android="http://schemasandroidcom/apk/res/android" 
  package="comtutorapplication" 
  android:versionCode="1" 
  android:versionName="0" > 
   
  <application 
    android:icon="@drawable/ic_launcher" 
    android:label="@string/app_name" 
    android:name="MainApplication" > 
    <activity 
      android:name="ApplicationDemoActivity" 
      android:label="@string/app_name" > 
      <intent-filter> 
        <action android:name="androidintentactionMAIN" /> 
        <category android:name="androidintentcategoryLAUNCHER" /> 
      </intent-filter> 
    </activity> 
  </application> 
   
</manifest> 

package com.tutor.application; 
import androidcontentContext; 
import androidwidgetToast; 
 
/** 
 * @author frankiewei 
 * 应用的一些工具类 
 */ 
public class ToolUtils { 
   
  /** 
   * 参数带Context 
   * @param context 
   * @param msg 
   */ 
  public static void showToast(Context context,String msg){ 
    ToastmakeText(context, msg, ToastLENGTH_SHORT)show(); 
  } 
   
  /** 
   * 调用全局的Context 
   * @param msg 
   */ 
  public static void showToast(String msg){ 
    ToastmakeText(MainApplicationgetContext(), msg, ToastLENGTH_SHORT)show(); 
  } 
} 

package com.tutor.application; 
 
import androidappActivity; 
import androidcontentContext; 
import androidutilAttributeSet; 
import androidviewLayoutInflater; 
import androidviewView; 
import androidwidgetButton; 
import androidwidgetFrameLayout; 
 
/** 
 * @author frankiewei 
 * 自定义的MainView 
 */ 
public class MainView extends FrameLayout implements ViewOnClickListener{ 
   
  private Context mContext; 
   
  private Activity mActivity; 
   
  /** 
   * 参数Button 
   */ 
  private Button mArgButton; 
   
  /** 
   * 全局Button 
   */ 
  private Button mGlobleButton; 
   
  /** 
   * 退出Button 
   */ 
  private Button mExitButton; 
   
  public MainView(Context context){ 
    super(context); 
    setupViews(); 
  } 
 
  public MainView(Context context, AttributeSet attrs) { 
    super(context, attrs); 
    setupViews(); 
  } 
   
   
  private void setupViews(){ 
    //获取View的上下文 
    mContext = getContext(); 
    //这里将Context转换为Activity 
    mActivity = (Activity)mContext; 
    LayoutInflater inflater = LayoutInflaterfrom(mContext); 
    View v = inflaterinflate(Rlayoutmain, null); 
    addView(v); 
     
    mArgButton = (Button)vfindViewById(Ridarg_button); 
    mGlobleButton = (Button)vfindViewById(Ridglo_button); 
    mExitButton = (Button)vfindViewById(Ridexit_button); 
     
    mArgButtonsetOnClickListener(this); 
    mGlobleButtonsetOnClickListener(this); 
    mExitButtonsetOnClickListener(this); 
  } 
 
  public void onClick(View v) { 
    if(v == mArgButton){ 
      ToolUtilsshowToast(mContext, "我是通过传递Context参数显示的!"); 
    }else if(v == mGlobleButton){ 
      ToolUtilsshowToast("我是通过全局Context显示的!"); 
    }else{ 
      mActivityfinish(); 
    } 
  } 
 
} 

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemasandroidcom/apk/res/android" 
  android:layout_width="fill_parent" 
  android:layout_height="fill_parent" 
  android:orientation="vertical" > 
 
  <TextView 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="Welcome to frankie wei's blog"  
    /> 
   
  <Button 
    android:id="@+id/arg_button" 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="传递Context参数" 
    /> 
   
  <Button 
    android:id="@+id/glo_button" 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="全局的Context" 
    /> 
   
  <Button 
    android:id="@+id/exit_button" 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="退出App" 
    /> 
 
</LinearLayout> 

package com.tutor.application;  
import androidappActivity; 
import androidosBundle; 
 
public class ApplicationDemoActivity extends Activity { 
  @Override 
  public void onCreate(Bundle savedInstanceState) { 
    superonCreate(savedInstanceState); 
     
    MainView mMainView = new MainView(this); 
    setContentView(mMainView); 
   
  } 
   
}